Merge pull request #814 from esden/spektrum_bind_pin_fix

[Spektrum] Configure the bind pin to be pullup/pulldown.

sw/airborne/arch/stm32/mcu_periph/gpio_arch.c

@@ -86,6 +86,18 @@ void gpio_setup_input(uint32_t port, uint16_t gpios) {
   gpio_set_mode(port, GPIO_MODE_INPUT, GPIO_CNF_INPUT_FLOAT, gpios);
 }
 
+void gpio_setup_input_pullup(uint32_t port, uint16_t gpios) {
+  gpio_enable_clock(port);
+  gpio_set(port, gpios);
+  gpio_set_mode(port, GPIO_MODE_INPUT, GPIO_CNF_INPUT_PULL_UPDOWN, gpios);
+}
+
+void gpio_setup_input_pulldown(uint32_t port, uint16_t gpios) {
+  gpio_enable_clock(port);
+  gpio_clear(port, gpios);
+  gpio_set_mode(port, GPIO_MODE_INPUT, GPIO_CNF_INPUT_PULL_UPDOWN, gpios);
+}
+
 void gpio_setup_pin_af(uint32_t port, uint16_t pin, uint32_t af, bool_t is_output) {
   gpio_enable_clock(port);
   /* remap alternate function if needed */
@@ -116,6 +128,16 @@ void gpio_setup_input(uint32_t port, uint16_t gpios) {
   gpio_mode_setup(port, GPIO_MODE_INPUT, GPIO_PUPD_NONE, gpios);
 }
 
+void gpio_setup_input_pullup(uint32_t port, uint16_t gpios) {
+  gpio_enable_clock(port);
+  gpio_mode_setup(port, GPIO_MODE_INPUT, GPIO_PUPD_PULLUP, gpios);
+}
+
+void gpio_setup_input_pulldown(uint32_t port, uint16_t gpios) {
+  gpio_enable_clock(port);
+  gpio_mode_setup(port, GPIO_MODE_INPUT, GPIO_PUPD_PULLDOWN, gpios);
+}
+
 void gpio_setup_pin_af(uint32_t port, uint16_t pin, uint8_t af, bool_t is_output __attribute__ ((unused))) {
   gpio_enable_clock(port);
   gpio_mode_setup(port, GPIO_MODE_AF, GPIO_PUPD_NONE, pin);

sw/airborne/arch/stm32/mcu_periph/gpio_arch.h

@@ -47,6 +47,20 @@ extern void gpio_setup_output(uint32_t port, uint16_t gpios);
  */
 extern void gpio_setup_input(uint32_t port, uint16_t gpios);
 
+/**
+ * Setup one or more pins of the given GPIO port as inputs with pull up resistor enabled.
+ * @param[in] port
+ * @param[in] gpios If multiple pins are to be changed, use logical OR '|' to separate them.
+ */
+extern void gpio_setup_input_pullup(uint32_t port, uint16_t gpios);
+
+/**
+ * Setup one or more pins of the given GPIO port as inputs with pull down resistors enabled.
+ * @param[in] port
+ * @param[in] gpios If multiple pins are to be changed, use logical OR '|' to separate them.
+ */
+extern void gpio_setup_input_pulldown(uint32_t port, uint16_t gpios);
+
 /**
  * Setup a gpio for input or output with alternate function.
  * This is an STM32 specific helper funtion and should only be used in stm32 arch code.

sw/airborne/arch/stm32/subsystems/radio_control/spektrum_arch.c

@@ -686,15 +686,27 @@ void SecondaryUart(_ISR)(void) {
  *****************************************************************************/
 void radio_control_spektrum_try_bind(void) {
 
-  /* Init GPIO for the bind pin */
-  gpio_setup_input(SPEKTRUM_BIND_PIN_PORT, SPEKTRUM_BIND_PIN);
-
-  /* exit if the BIND_PIN is high, it needs to
-     be pulled low at startup to initiate bind */
 #ifdef SPEKTRUM_BIND_PIN_HIGH
+  /* Init GPIO for the bind pin, we enable the pulldown resistor.
+   * (esden) As far as I can tell only navstick is using the PIN LOW version of
+   * the bind pin, but I assume this should not harm anything. If I am mistaken
+   * than I appologise for the inconvenience. :)
+   */
+  gpio_setup_input_pulldown(SPEKTRUM_BIND_PIN_PORT, SPEKTRUM_BIND_PIN);
+
+  /* exit if the BIND_PIN is low, it needs to
+     be pulled high at startup to initiate bind */
   if (gpio_get(SPEKTRUM_BIND_PIN_PORT, SPEKTRUM_BIND_PIN) == 0)
     return;
 #else
+  /* Init GPIO for the bind pin, we enable the pullup resistor in case we have
+   * a floating pin that does not have a hardware pullup resistor as it is the
+   * case with Lisa/M and Lisa/MX prior to version 2.1.
+   */
+  gpio_setup_input_pullup(SPEKTRUM_BIND_PIN_PORT, SPEKTRUM_BIND_PIN);
+
+  /* exit if the BIND_PIN is high, it needs to
+     be pulled low at startup to initiate bind */
   if (gpio_get(SPEKTRUM_BIND_PIN_PORT, SPEKTRUM_BIND_PIN) != 0)
     return;
 #endif